/*
 * Copyright (C)2003,2004 USAGI/WIDE Project
 *
 * Header for use in defining a given L3 protocol for connection tracking.
 *
 * Author:
 *	Yasuyuki Kozakai @USAGI	<yasuyuki.kozakai@toshiba.co.jp>
 *
 * Derived from include/netfilter_ipv4/ip_conntrack_protocol.h
 */

#ifndef _NF_CONNTRACK_L3PROTO_H
#define _NF_CONNTRACK_L3PROTO_H
#include <linux/netlink.h>
#include <net/netlink.h>
#include <linux/seq_file.h>
#include <net/netfilter/nf_conntrack.h>

struct nf_conntrack_l3proto {
	/* L3 Protocol Family number. ex) PF_INET */
	u_int16_t l3proto;

	/* Protocol name */
	const char *name;

	/*
	 * Try to fill in the third arg: nhoff is offset of l3 proto
	 * hdr.  Return true if possible.
	 */
	 bool(*pkt_to_tuple) (const struct sk_buff * skb, unsigned int nhoff,
			      struct nf_conntrack_tuple * tuple);

	/*
	 * Invert the per-proto part of the tuple: ie. turn xmit into reply.
	 * Some packets can't be inverted: return 0 in that case.
	 */
	 bool(*invert_tuple) (struct nf_conntrack_tuple * inverse,
			      const struct nf_conntrack_tuple * orig);

	/* Print out the per-protocol part of the tuple. */
	int (*print_tuple) (struct seq_file * s,
			    const struct nf_conntrack_tuple *);

	/*
	 * Called before tracking. 
	 *      *dataoff: offset of protocol header (TCP, UDP,...) in skb
	 *      *protonum: protocol number
	 */
	int (*get_l4proto) (const struct sk_buff * skb, unsigned int nhoff,
			    unsigned int *dataoff, u_int8_t * protonum);

	int (*tuple_to_nlattr) (struct sk_buff * skb,
				const struct nf_conntrack_tuple * t);

	int (*nlattr_to_tuple) (struct nlattr * tb[],
				struct nf_conntrack_tuple * t);
	const struct nla_policy *nla_policy;

#ifdef CONFIG_SYSCTL
	struct ctl_table_header *ctl_table_header;
	struct ctl_path *ctl_table_path;
	struct ctl_table *ctl_table;
#endif				/* CONFIG_SYSCTL */

	/* Module (if any) which this is connected to. */
	struct module *me;
};

extern struct nf_conntrack_l3proto *nf_ct_l3protos[AF_MAX];

/* Protocol registration. */
extern int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto);
extern void nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto);
extern struct nf_conntrack_l3proto *nf_ct_l3proto_find_get(u_int16_t l3proto);
extern void nf_ct_l3proto_put(struct nf_conntrack_l3proto *p);

/* Existing built-in protocols */
extern struct nf_conntrack_l3proto nf_conntrack_l3proto_generic;

static inline struct nf_conntrack_l3proto *__nf_ct_l3proto_find(u_int16_t
								l3proto)
{
	if (unlikely(l3proto >= AF_MAX))
		return &nf_conntrack_l3proto_generic;
	return rcu_dereference(nf_ct_l3protos[l3proto]);
}

#endif /*_NF_CONNTRACK_L3PROTO_H*/
